1. Field of the Invention
This invention relates to guns utilizing liquid propellant and a differential piston to provide regenerative injection of the propellant into the combustion chamber after an initial ignition of propellant in the combustion chamber.
2. Prior Art
An extensive summary of the prior art appears in the patent applications of M. Bulman, Ser. No. 840,074, R. A. Algera, Ser. No. 840,075, and R. E. Mayer, Ser. No. 840,104, all filed Oct. 6, 1977. More recent exemplars of the prior art are the patents of R. E. Mayer, U.S. Pat. No. 4,341,147, issued July 27, 1982; I. K. Magoon, U.S. Pat. No. 4,523,507, issued June 18, 1985; R. E. Mayer et al, U.S. Pat. No. 4,523,508, issued June 18, 1985; and I. K. Magoon, U.S. Pat. No. 4,586,422, issued May 6, 1986.
These more recent exemplars of Mayer and Magoon show a stationary central control rod aft of the combustion chamber which cooperates with an outer annular injection piston to pump liquid propellant from a mutually defined storage chamber, through a mutually defined injection annular orifice, to the combustion chamber.
The exemplar of Mayer, U.S. Pat. No. 4,341,147, shows both a stationary central control rod and a moveable central piston which controls the flow of propellant through a series of holes in the shaft of a T-shaped propellant injection piston as a function of the relative displacement of the inner and outer elements.
The applications of Bulman and Mayer show a stationary gun barrel with an outer annular piston and an annular, piston-like, fill valve, both substantially forward of the combustion chamber. The piston pumps liquid propellant from a storage chamber defined by the piston and the valve into the combustion chamber.